Effects on Voice Fundamental Frequency and Satisfaction with Voice in Trans Men during Testosterone Treatment—A Longitudinal Study

Abstract

To investigate effects of testosterone treatment regarding voice virilization, voice problems, and voice satisfaction in transsexual female-to-male individuals, referred to as trans men. Longitudinal. Fifty trans men, diagnosed with transsexualism, 18-64 years, met the inclusion criteria. Voice data before treatment and after 3, 6, or 12 months were available from 49 participants, and for 28 participants also after 18 and/or 24 months of treatment. Digital audio recordings of speech range profiles and voice range profiles were carried out in a sound-treated booth following clinical routines. Acoustic analyses of fundamental frequency (F0) and sound pressure level were made. Endocrine data and answers from questionnaires concerning voice function and voice problems were collected from medical records. Mean F0 and mode F0 of the habitual voice decreased significantly after 3 months, 6 months, and up to 12 months, when group data were congruent with reference data for males. Mean F0 was 125 Hz after 12 months with a large interindividual variation. Sound pressure level values did not change significantly. Voice satisfaction correlated with lower F0 values. Twenty-four percent of the participants reported voice symptoms, for example, vocal instability and fatigue, and had received voice therapy. F0 values did not correlate with androgen levels. Most trans men developed a male voice and were satisfied. However, it is important to detect the substantial group of trans men with voice problems and with insufficient voice virilization and who may need voice therapy. Therefore, we recommend systematic voice assessments during testosterone treatment.